From 0d91ef78ddb487e08969c9efb385ef7de69750b9 Mon Sep 17 00:00:00 2001 From: Oblomov Date: Thu, 28 Apr 2022 18:53:33 +0200 Subject: [PATCH] Refactor local time getter functions (#12221) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This commit introduces mt_localtime() in src/gettime.h, a wrapper around the OS-specific thread-safe versions of localtime() (resp. localtime_s on Windows and localtime_r in other systems). Per the Open Group recommendation, «portable applications should call tzset() explicitly before using ctime_r() or localtime_r() because setting timezone information is optional for those functions», so we also do a one-shot call of tzset() (_tzset() on Windows to avoid warning C4996). The function is used to replace the localtime() calls in getTimestamp() and makeScreenshot(). (The only reminaing call to localtime() in the tree now is the one in the local copy of the Lua source code.) --- src/client/client.cpp | 5 ++--- src/gettime.h | 32 +++++++++++++++++++++++++++----- 2 files changed, 29 insertions(+), 8 deletions(-) diff --git a/src/client/client.cpp b/src/client/client.cpp index 935a82653..0a1fc73d1 100644 --- a/src/client/client.cpp +++ b/src/client/client.cpp @@ -1810,11 +1810,10 @@ void Client::makeScreenshot() if (!raw_image) return; - time_t t = time(NULL); - struct tm *tm = localtime(&t); + const struct tm tm = mt_localtime(); char timetstamp_c[64]; - strftime(timetstamp_c, sizeof(timetstamp_c), "%Y%m%d_%H%M%S", tm); + strftime(timetstamp_c, sizeof(timetstamp_c), "%Y%m%d_%H%M%S", &tm); std::string screenshot_dir; diff --git a/src/gettime.h b/src/gettime.h index 66efef1d7..772ff9b50 100644 --- a/src/gettime.h +++ b/src/gettime.h @@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc., #include #include +#include enum TimePrecision { @@ -30,13 +31,34 @@ enum TimePrecision PRECISION_NANO }; +inline struct tm mt_localtime() +{ + // initialize the time zone on first invocation + static std::once_flag tz_init; + std::call_once(tz_init, [] { +#ifdef _WIN32 + _tzset(); +#else + tzset(); +#endif + }); + + struct tm ret; + time_t t = time(NULL); + // TODO we should check if the function returns NULL, which would mean error +#ifdef _WIN32 + localtime_s(&ret, &t); +#else + localtime_r(&t, &ret); +#endif + return ret; +} + + inline std::string getTimestamp() { - time_t t = time(NULL); - // This is not really thread-safe but it won't break anything - // except its own output, so just go with it. - struct tm *tm = localtime(&t); + const struct tm tm = mt_localtime(); char cs[20]; // YYYY-MM-DD HH:MM:SS + '\0' - strftime(cs, 20, "%Y-%m-%d %H:%M:%S", tm); + strftime(cs, 20, "%Y-%m-%d %H:%M:%S", &tm); return cs; }